Dithiopiperazines



2,808,409 DITHIOPIPERAZINES John J. DAmico, Charleston, santo Chemical Company,

St. Louis, Mo., a corporation of Delaware N Drawing. Application February 24,

Serial No. 412,376 4 Claims. ((31. 260 268 where R, R and R" are selected from a group consisting of hydrogen and hydrocarbon radicals.

The new compounds are conveniently prepared by condensing piperazine or a hydrocarbon substituted derivative thereof with sulfur monochloride. Sulfur monobro-- mide can be substituted but of course is more expensive.

. EXAMPLE 1 The reaction was carried out in a 2 liter i-ne'cked flask equipped with a mechanical stirrer, two dropping funnels, thermometer and ice bath. Into the reactor was charged a solution of 114 grams of 2,5-dimethyl piperazine in 1,000 ml. of trichloroethylene. The solution was cooled to about C. and to it over a period of about an hour was added a solution of 67.4 grams of sulfur monochloride in 50 ml. of trichloroethylene. The contents of the reaction vessel were stirred vigorously during the addi tion and the temperature kept at 5-10 C. Stirring was continued for 30 minutes at C. and by-product hydrochloride salt neutralized by the addition of 160 grams of 25% aqueous sodium hydroxide and 400 ml. of water. The solids were then removed by filtration, washed with water until the washings were neutral to litmus and dried at 50 C. to obtain 67 grams of product M. P. 216-218 C. The compound had the empirical formula C12H24N4S4. Analysis gave 15.9% nitrogen and 37.5% sulfur as compared to calculated values of 15.9% nitrogen and 36.4% sulfur. The compound is insoluble in water and all common organic solvents from which properties coupled with the analysis the structural formula is believed to be Substantially 50 parts by weight of piperazine was dissolved in 950 parts by weight of trichloroethylene and cooled to 10 C. A solution of 39 parts by weight of W. Va., assignor to' Monnited States Patent Oflice 2 chloride in trichloroethylene were added concurrently with 92.8 parts by weight of aqueous caustic soda at 10-20 C. over a period of about 25 minutes and stirring continued for lfl'minutes. The reaction mixture I was then stirred with 250 parts by weight of water for 15 minutes, the solids filtered 01f, washed with water until the washings were neutral to litmus and dried to yield an N-thio piperazine, M. P. 2l-8-221 C., having the empirical formula C8H16N4S4 in a yield of 75.6% of the theoretical.

EXAMPLE. 3 To a stirred solution containing 81.2 grams 0.5 mole of 4-phenyl piperazine in 800 ml. of anhydrous ether was added dropwise 16.9 grams (0.125 mole) of sulfur mono- 1,1-dithiobis(4-phenyl piperazine) melted at 117-119" C.

Analysis gave 14.45% nitrogen as compared to 14.49%

nitrogen calculated for CaaHasNisz. V The new compounds are efiieie'nt accelerators and vulcanizing agents. For example the accelerating effect in natural rubber is illustrated by. stocks A, B and C below.

Stocks A and C were compounded from smoked sheets and stock B from pale crepe.

Rubber "parts by weight 100 100 100 Zinc oxide .do 5 5 5 Stearic acid d0= 1- 1 1 Sulfur; r. d0 3 3 Product of Example 1 do.-- 1 0. 7 Product of Example -do 1 Dlphenyl guanldined 0 3 The stocks so compounded were cured in a press in the usual manner by heating for minutes at 275 F.

Table I Modulus of Elasticity Tensile at Ultimate Stock in lbs/in. Break in Elongation,

at Elongalbs/in. Percent tion of 700% The new compounds are especially active for the vulcanization of Butyl rubber. Their properties are illustrated by stocks E and F below wherein the accelerating activity is compared to that of stock D containing tetramethyl thiuram disulfide, a widely used Butyl rubber accelerator.

2,808,409 Patented Oct. 1, 1957 These stocks were cured in the usual manner by heating for different periods of time in a press at 330 F. to

obtain vulcanization exhibtiing the physical properties described below:

,The powerful vulcanizing action of the new compounds is illustrated by tests carried 'out in the following compositions: 7

Stock l G H J Smoked sheets-" parts by weight 100 100 100 .dor 50 50 50 d 5 5 Saturated hy ocarbon softener. do .v 3 3 3 Stearic acid-.- ..do 2 2 2 Antioxidant do 1. 5 1. 5 N-Cyclohexyl 2-benzothiazole sulfenamide'. .do 0 8 0.8 0 8 Sulfur do 2.5 2.5 Product of Example 1 do v 3.3 Product of Example 3 ;do e 6.0

The stocks so compounded were cured by heating for 60 minutes at 291.2 F, to obtain vulcanizates having the physical properties described below: V a

r Table III Modulus of Elasticity Tensile at "Ultimate Stock inlbsJin. Breakin Elongation,

at Elongalbs/111. Percent 'tion of v r Thenew compounds either as accelerators or vulcaniz ing agents are resistant to pro-vulcanization; For instance the uncured stock H was evaluated for resistance to pre- 4 vulcanization by means of a Mooney plastometer at 275 F. The readings as compared to the control stock were as follows:

Table IV Mooney Plastometer headings after Heating Stock 4 7 8 9 10 11 12 13 14 minminminminminminminminminutes utes utes utes utes utcs utes utes utes G 4a 4a 44 4s 90 150 H 49 49 49 49 49 50 53 64 where R and R are selected from a group consisting of hydrogen and lower alkyl groups and R' is selected from a group consisting of hydrogen and phenyl groups.

2. A compound of the structure 3.;A product obtained by condensing with formation of by-product hydrogen chloride sulfur monochloride with piperazine.

4. A product obtained by condensing with formation of by-product hydrogen chloride sulfur monochloride with 2,5-dimethyl piperazine.

No references cited. 

1.THE PRODUCT OBTAINED BY CONDENSING WITH FORMATION OF BY-PRODUCT HYDROGEN HALIDE A SULFUR HALIDE SELECTED FROM THE GROUP CONSISTING OF SULFURMONOCHLORIDE AND SULFUR MONOBROMIDE AND A PIPERAZINE OF THE STRUCTURE 